1. Field of the Invention
This invention relates to character recognition systems and procedures. More particularly, this invention relates to processing groups of character-bearing documents by intelligent character recognition (ICR) techniques.
2. Description of the Prior Art
Characters on documents such as forms to be filled in with hand-printed characters are now commonly read automatically by character recognition apparatus, of which there is a considerable variety. In such apparatus, the documents generally are scanned by radiant energy such as visible light or infra-red wavelengths, arranged for example to develop a series of closely-spaced parallel scan lines and to produce scan signals for closely-spaced spots along each line. The resulting scan data signals typically form a rectilinear data array of binary bits at the intersections of a rectangular coordinate grid.
These scan data signals are stored and analyzed in accordance with a recognition algorithm. Before the algorithm is applied, the character images normally are put through a "segmentation" process, to assure separation, and then are "boxed" for recognition processing. Recognition algorithms have become highly refined, so that a large proportion of the scanned characters will be correctly recognized. Nonetheless, there will be characters which the algorithm cannot recognize, or may identify incorrectly, and for most applications it becomes necessary to carry out supplementary procedures to complete the processing.
Conventionally, to determine the identity of a character which failed to be recognized algorithmically, the image of a substantial area of text or an entire field on a business form containing such character will be displayed on a CRT for inspection by an operator. This large area display enables the keying operator to be more certain of character identity than by displaying just a rejected character image, especially where segmentation may not have been performed correctly due to printing problems or other causes.
Such supplementary procedures take considerable time. For example, when fields and other large areas are displayed one at a time with isolated character rejects, an operator rarely exceeds keying one character every two seconds. A considerably greater speed of keying and correcting character identities is badly needed for high volume document processing.